Articulated medical devices provide access to sites within a patient's body that are difficult to reach using rigid non-articulating devices. An articulated endoscope can provide direct access to internal organs, and an articulated catheter may provide access to tortuous vascular structures. These articulated devices are flexible to provide easy manipulation. Once the medical device is positioned at the surgical site, it can be desirable to lock the device's shape. A locked device, for example, is better able to lift or retract tissue than a flexible one.
Traditional medical devices often lack the ability to efficiently lock and unlock. Most locks operate by compressing adjacent articulation links. However, significant compressive forces must be applied to lock a joint that is specifically designed for movement. These locks often apply high tensile forces to wires in the joint to ensure adequate compression of adjacent links.